U.S. patent application number 14/919816 was filed with the patent office on 2016-04-28 for helium recovery process and apparatus.
The applicant listed for this patent is UOP LLC. Invention is credited to Pavel V. Ryabchenko, Manu G. R. Van Leuvenhaege, Cedric F. Vercammen.
Application Number | 20160115029 14/919816 |
Document ID | / |
Family ID | 55791425 |
Filed Date | 2016-04-28 |
United States Patent
Application |
20160115029 |
Kind Code |
A1 |
Van Leuvenhaege; Manu G. R. ;
et al. |
April 28, 2016 |
HELIUM RECOVERY PROCESS AND APPARATUS
Abstract
A process and apparatus for increasing recovery of helium are
described. The process includes introducing the stream containing
helium and at least one oxidizable component into an oxidation zone
in the presence of oxygen to oxidize the oxidizable component
forming a first vapor stream and a first liquid stream. The first
vapor stream is introduced into a pressure swing adsorption zone to
form a purified helium stream and a tail gas stream. The tail gas
stream is compressed. The compressed tail gas stream is introduced
into a membrane separation zone to form a helium rich permeate
stream and a retentate stream. The helium rich permeate stream is
compressed and introduced into the oxidation system.
Inventors: |
Van Leuvenhaege; Manu G. R.;
(Antwerp, BE) ; Vercammen; Cedric F.; (Antwerp,
BE) ; Ryabchenko; Pavel V.; (Moscow, RU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UOP LLC |
Des Plaines |
IL |
US |
|
|
Family ID: |
55791425 |
Appl. No.: |
14/919816 |
Filed: |
October 22, 2015 |
Current U.S.
Class: |
423/262 ;
422/187 |
Current CPC
Class: |
C01B 2210/0014 20130101;
B01D 2253/108 20130101; Y02C 20/40 20200801; B01D 53/047 20130101;
B01D 53/864 20130101; B01D 2253/102 20130101; Y02P 20/151 20151101;
C01B 2210/001 20130101; B01D 2257/108 20130101; B01D 2257/502
20130101; B01D 53/72 20130101; Y02C 20/20 20130101; B01D 53/75
20130101; B01D 2257/7022 20130101; B01D 2257/7025 20130101; B01D
2256/18 20130101; B01D 53/229 20130101; B01D 2253/104 20130101;
B01D 2257/504 20130101; Y02C 10/10 20130101; B01D 53/228 20130101;
B01D 53/002 20130101; B01D 2253/106 20130101; Y02P 20/152 20151101;
Y02P 20/156 20151101; C01B 2210/0004 20130101; C01B 2210/0031
20130101; C01B 23/0094 20130101; B01D 2251/102 20130101; B01D
2257/80 20130101 |
International
Class: |
C01B 23/00 20060101
C01B023/00; B01D 53/22 20060101 B01D053/22; B01D 53/047 20060101
B01D053/047 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 27, 2014 |
RU |
2014143204 |
Claims
1. A process of increasing recovery of helium from a stream
containing helium comprising: introducing the stream containing
helium and at least one oxidizable component into an oxidation zone
in the presence of oxygen to oxidize the at least one oxidizable
component forming a first vapor stream and a first liquid stream;
introducing at least a portion of the first vapor stream into a
pressure swing adsorption zone to form a purified helium stream and
a tail gas stream, the tail gas stream containing helium;
compressing at least a portion of the tail gas stream; introducing
at least a portion of the compressed tail gas stream into a
membrane separation zone to form a helium rich permeate stream and
a retentate stream; compressing at least a portion of the helium
rich permeate stream; and introducing the compressed helium rich
permeate stream into the oxidation zone.
2. The process of claim 1 further comprising condensing the first
vapor stream before introducing the at least the portion of the
first vapor stream into the pressure swing adsorption zone.
3. The process of claim 2 further comprising: separating the
condensed first vapor stream into a second vapor stream and a
second liquid stream; and wherein introducing the at least the
portion of the first vapor stream into the pressure swing
adsorption zone comprises introducing the second vapor stream into
the pressure swing adsorption zone.
4. The process of claim 1 wherein the oxidation zone comprises a
catalytic oxidation zone.
5. The process of claim 1 further comprising removing a portion of
the tail gas stream.
6. The process of claim 5 wherein the portion of the tail gas
stream is removed before compressing the at least the portion of
the tail gas stream.
7. The process of claim 5 wherein the portion of the tail gas
stream is removed after compressing the at least the portion of the
tail gas stream.
8. The process of claim 5 wherein the portion of the tail gas
stream is removed after compressing the at least the portion of the
helium rich permeate stream.
9. The process of claim 1 further comprising removing a portion of
the helium rich permeate gas stream.
10. The process of claim 9 wherein the portion of the helium rich
permeate gas stream is removed before compressing the at least the
portion of the helium rich permeate gas stream.
11. The process of claim 9 wherein the portion of the helium rich
permeate stream is removed after compressing the at least the
portion of the helium rich permeate stream.
12. The process of claim 1 wherein the tail gas stream has a helium
content of about 30-35%.
13. The process of claim 1 wherein the helium rich permeate stream
has a helium content of at least about 70%.
14. The process of claim 1 wherein the stream containing helium has
a helium content of about 50-90%, the tail gas stream has a helium
content of about 30-60%, the helium rich permeate stream has a
helium content of at least about 70%, and the purified helium
stream has a helium content of at least about 99%.
15. A process of increasing recovery of helium from a stream
containing helium comprising: introducing the stream containing
helium into a catalytic oxidation zone in the presence of oxygen to
oxidize the at least one oxidizable component forming a first vapor
stream and a first liquid stream, wherein the stream containing
helium has a helium content of about 55-60%; condensing the first
vapor stream from the catalytic oxidation zone; separating the
condensed first vapor stream into a second liquid stream and a
second vapor stream; introducing the second vapor stream into a
pressure swing adsorption zone to form a purified helium stream
having a helium content of at least about 99% and a tail gas stream
having a helium content of about 30-35%; compressing at least a
portion of the tail gas stream; introducing at least a portion of
the compressed tail gas stream into a membrane separation zone to
form a helium rich permeate stream having a helium content of at
least about 70% and a retentate stream; compressing the helium rich
permeate stream; and introducing the compressed helium rich
permeate stream into the catalytic oxidation zone.
16. The process of claim 15 further comprising removing a portion
of the tail gas stream.
17. The process of claim 16 wherein the portion of the tail gas
stream is removed before compressing the at least the portion of
the tail gas stream.
18. The process of claim 15 further comprising removing a portion
of the helium rich permeate gas stream.
19. The process of claim 18 wherein the portion of the helium rich
permeate gas stream is removed before compressing the at least the
portion of the helium rich permeate gas stream.
20. An apparatus for recovery of helium from a stream containing
helium comprising: an oxidation zone having a feed inlet, an oxygen
inlet, a liquid outlet, and a gas outlet; a condenser having an
inlet and an outlet, the inlet of the condenser being in fluid
communication with the gas outlet of the oxidation zone; a
separator having an inlet, a liquid outlet, and a gas outlet, the
inlet of the separator in fluid communication with the outlet of
the condenser; a pressure swing adsorption zone having an inlet, a
purified helium outlet, and a tail gas outlet, the inlet of the
pressure swing adsorption zone being in fluid communication with
the outlet of the separator; a first compression zone having an
inlet and an outlet, the inlet of the first compression zone being
in fluid communication with the tail gas outlet of the pressure
swing adsorption system; a membrane separation zone having an
inlet, a permeate outlet, and a retentate outlet, the inlet of the
membrane separation zone being in fluid communication with the tail
gas outlet of the pressure swing adsorption zone; and a second
compression zone having an inlet and an outlet, the inlet of the
second compression zone being in fluid communication with the
permeate outlet of the membrane separation zone, and the outlet of
the second compression zone being in fluid communication with the
oxidation zone.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from Russian Application
No. 2014143204 filed Oct. 27, 2014, the contents of which are
hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] Various processes are used to recover helium from gas
streams. One of the most common processes is the cryogenic
distillation process. Cryogenic distillation provides high recovery
of helium. Membrane separation has also been used for helium
recovery. Pressure swing adsorption (PSA) processes have also been
used.
[0003] The recovery of helium from a process stream using PSA
processes is typically limited to about 75-80%, which means that
about 20-25% of the helium is being lost. The rate can be improved
slightly by recycling some of the PSA tail gas. However, the
improvement in recovery is limited because recycling more tail gas,
which has a low level of helium, lowers the helium concentration in
the PSA feed gas, resulting in lower recovery in the PSA system
itself.
[0004] There is a need for improved processes which provide high
recovery of helium from process streams containing hydrogen.
SUMMARY OF THE INVENTION
[0005] One aspect of the present invention is a process of
increasing recovery of helium from a stream containing helium. In
one embodiment, the process includes introducing the stream
containing helium and at least one oxidizable component into an
oxidation zone in the presence of oxygen to oxidize the at least
one oxidizable component forming a first vapor stream and a first
liquid stream. At least a portion of the first vapor stream is
introduced into a pressure swing adsorption zone to form a purified
helium stream and a tail gas stream, the tail gas stream containing
helium. At least a portion of the tail gas stream is compressed. At
least a portion of the compressed tail gas stream is introduced
into a membrane separation zone to form a helium rich permeate
stream and a retentate stream. At least a portion of the helium
rich permeate stream is compressed. The compressed helium rich
permeate stream is introduced into the oxidation system.
[0006] Another aspect of the invention is an apparatus for recovery
of helium from a stream containing helium. The apparatus includes
an oxidation zone having a feed inlet, an oxygen inlet, a liquid
outlet, and a gas outlet; a condenser having an inlet and an
outlet, the inlet of the condenser being in fluid communication
with the gas outlet of the oxidation zone; a separator having an
inlet, a liquid outlet, and a gas outlet, the inlet of the
separator in fluid communication with the outlet of the condenser;
a pressure swing adsorption zone having an inlet, a purified helium
outlet, and a tail gas outlet, the inlet of the pressure swing
adsorption zone being in fluid communication with the outlet of the
separator; a first compressor having an inlet and an outlet, the
inlet of the first compressor being in fluid communication with the
tail gas outlet of the pressure swing adsorption system; a membrane
separation zone having an inlet, a permeate outlet, and a retentate
outlet, the inlet of the membrane separation zone being in fluid
communication with the tail gas outlet of the pressure swing
adsorption zone; and a second compressor having an inlet and an
outlet, the inlet of the second compressor being in fluid
communication with the permeate outlet of the membrane separation
zone, and the outlet of the second compressor being in fluid
communication with the oxidation zone.
BRIEF DESCRIPTION OF THE DRAWING
[0007] The FIGURE illustrates one embodiment of a process of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0008] The present invention provides an improved process of helium
recovery from a gas stream.
[0009] The process involves the use of an oxidation zone, a PSA
zone, and a membrane separation zone. Oxidizable components in the
feed are oxidized in the oxidation zone. The gas stream is sent to
the PSA zone where purified helium is separated out. The PSA tail
gas is sent to a membrane separation zone where a helium rich
stream is formed. The helium rich stream, which contains a higher
concentration of helium than the feed can be recycled without
having a negative effect on the helium recovery in the PSA
zone.
[0010] As shown in the FIGURE, the process 100 involves the
introduction of a gas stream 105 containing helium. In addition to
helium, stream 105 can include, but is not limited to, one or more
of hydrogen, methane, carbon monoxide, carbon dioxide, nitrogen,
argon, and other noble gases, for example. The source of the gas
stream 105 can be for example, a natural gas stream or a natural
gas stream that has been converted to a hydrogen stream. Either or
both could be upgraded in helium concentration by another process
system upstream. The feed stream will typically contain about 50-90
vol % helium, or about 55-60 vol %.
[0011] The gas stream 105 and an oxygen stream 110 are introduced
into an oxidation zone 115. The gas stream 105 and the oxygen
stream 110 can be introduced into the oxidation zone 115 either
separately, as shown, or they can be mixed together prior to being
introduced into the reaction zone. The oxygen stream is desirably
purified oxygen, but streams containing less oxygen including air
could also be used. Desirably, the oxygen stream contains more than
about 50% oxygen, or more than about 60%, or more than about 70%,
or more than about 80%, or more than about 85%, or more than about
90%, or more than about 95%, or more than about 97%, or more than
about 99%.
[0012] The gas stream 105 contains oxidizable compounds, including,
but not limited to, hydrogen, CH.sub.4, ethane, and propane, carbon
monoxide and the like. The oxidizable compounds are oxidized in the
oxidation zone 115. The oxidation reaction forms a first vapor
stream 120 and a liquid stream 125. The first vapor stream 120
comprises helium, water, carbon monoxide, carbon dioxide, and very
low levels (in the ppm range) of hydrogen and hydrocarbons. The
liquid stream 125 comprises water, which is removed from the
system.
[0013] The oxidizable compounds are oxidized in the oxidation zone
115. For example, hydrogen is converted to water, hydrocarbons to
carbon dioxide, carbon monoxide to carbon dioxide, etc. The
oxidation zone can be any oxidation zone known to those of skill in
the art. Suitable oxidation zones include, but are not limited to,
burner systems, and catalytic oxidation zones.
[0014] The first vapor stream 120 is sent to a condenser 130 to
cool and condense the first vapor stream 120. The condensed stream
135 is set to a separator 140, for example a filter coalescer, or
other type of separator. The condensed stream 135 is separated into
a second vapor stream 145 and a second liquid stream 150. The
second vapor stream 145 comprises helium, carbon monoxide, carbon
dioxide, and very low levels (in the ppm range) of hydrogen and
hydrocarbons and a lower level of water than first vapor stream
120. The second liquid stream 150 comprises water.
[0015] The second vapor stream 145 is introduced into a PSA zone
155 for purification. In operation, the second vapor stream 145 is
introduced into a packed bed, and the adsorbent material contained
therein removes hydrocarbons, water, residual helium, and carbon
dioxide, known as the sorbate, from the stream as it flows through
the packed bed. After a given time period, the adsorbent material
becomes saturated with the sorbate, and the adsorption process must
be halted in order to regenerate the adsorbent and remove the
sorbate. PSA processes utilize a de-pressurized regeneration gas
that is introduced to the packed bed in a direction reverse to the
flow of the process stream. After a regeneration cycle is complete,
a new adsorption cycle can begin. Typical purities for PSA helium
product streams range from 99 to 99.999% by volume.
[0016] Packed beds of adsorbent materials are typically used in PSA
processes. The adsorbent materials are generally in the form of
spherical beads, or extruded pellets. Alternatively, it may be
shaped into honeycomb monolithic structures. The adsorbent may
comprise powdered solid, crystalline or amorphous compounds capable
of adsorbing and desorbing the adsorbable compound. Examples of
such adsorbents include silica gels, activated aluminas, activated
carbon, molecular sieves, and mixtures thereof. Molecular sieves
include zeolite molecular sieves. The adsorbent materials are
typically zeolites. In a processing scheme such as the one depicted
in the FIGURE, the PSA unit 155 is typically operated at feed
pressures ranging from about 1.0 MPa (g) to about 8.6 MPa (g).
[0017] Generally, such PSA units operate on a cyclic basis, with
individual adsorber vessels cycled between adsorption and
desorption steps. Multiple adsorbers are commonly used in order to
provide constant product and tail gas flows. Adsorbents are
selected based on the type and quantity of impurities present in
the feed stream and also the required degree of removal of such
impurities. Such PSA units and their operation are more fully
described, for example, in U.S. Pat. Nos. 4,964,888 and 6,210,466,
for example.
[0018] The purified helium 160 is sent for recovery. The tail gas
stream 165 typically contains about 30-60% helium, or about 30-35%.
It is typically at a pressure of about 130 kPa to about 500 kPa.
The tail gas stream can be divided into stream 170 and stream 175.
Stream 175 can be a purge stream to avoid the build-up various
components in the system.
[0019] Stream 170 is then sent to a compression zone 180 where it
is compressed to about 3 MPa. The compressed stream 185 is sent to
the membrane separation zone (190). Membrane-based technologies
have a low capital cost, and they provide high energy efficiency
compared to conventional separation methods.
[0020] Polymers provide a range of properties including low cost,
permeability, mechanical stability, and ease of processability that
are important for gas separation. Glassy polymers (i.e., polymers
at temperatures below their TO have stiffer polymer backbones and
therefore allow smaller molecules such as hydrogen and helium pass
through more quickly, while larger molecules such as hydrocarbons
pass through more slowly as compared to polymers with less stiff
backbones. Cellulose acetate (CA) glassy polymer membranes are used
extensively in gas separation. Currently, such CA membranes are
used for natural gas upgrading, including the removal of carbon
dioxide. Although CA membranes have many advantages, they are
limited in a number of properties including selectivity,
permeability, and in chemical, thermal, and mechanical stability.
High performance polymers such as polyimides (PIs),
poly(trimethylsilylpropyne), and polytriazole have been developed
to improve membrane selectivity, permeability, and thermal
stability. These polymeric membrane materials have shown promising
intrinsic properties for separation of gas pairs such as
CO.sub.2/CH.sub.4, O.sub.2/N.sub.2, H.sub.2/CH.sub.4, and
propylene/propane (C.sub.3H.sub.6/C.sub.3H.sub.8).
[0021] The membranes most commonly used in commercial gas and
liquid separation applications are asymmetric polymeric membranes
which have a thin nonporous selective skin layer that performs the
separation. Separation is based on a solution-diffusion mechanism.
This mechanism involves molecular-scale interactions of the
permeating gas with the membrane polymer. The mechanism assumes
that in a membrane having two opposing surfaces, each component is
sorbed by the membrane at one surface, transported by a gas
concentration gradient, and desorbed at the opposing surface.
According to this solution-diffusion model, the membrane
performance in separating a given pair of gases (e.g.,
CO.sub.2/CH.sub.4, O.sub.2/N.sub.2, H.sub.2/CH.sub.4,) is
determined by two parameters: the permeability coefficient
(abbreviated hereinafter as permeability or P.sub.A) and the
selectivity (.alpha..sub.A/B). The P.sub.A is the product of the
gas flux and the selective skin layer thickness of the membrane,
divided by the pressure difference across the membrane. The
.alpha..sub.A/B is the ratio of the permeability coefficients of
the two gases (.alpha..sub.A/B=P.sub.A/P.sub.B) where P.sub.A is
the permeability of the more permeable gas and P.sub.A is the
permeability of the less permeable gas. Gases can have high
permeability coefficients because of a high solubility coefficient,
a high diffusion coefficient, or because both coefficients are
high. In general, the diffusion coefficient decreases while the
solubility coefficient increases with an increase in the molecular
size of the gas. In high performance polymer membranes, both high
permeability and selectivity are desirable because higher
permeability decreases the size of the membrane area required to
treat a given volume of gas, thereby decreasing capital cost of
membrane units, and because higher selectivity results in a higher
purity product gas.
[0022] One of the components to be separated by a membrane must
have a sufficiently high permeance at the preferred conditions or
an extraordinarily large membrane surface area is required to allow
separation of large amounts of material. Permeance, measured in Gas
Permeation Units (GPU, 1 GPU=10-6 cm.sup.3 (STP)/cm.sup.2 s (cm
Hg)), is the pressure normalized flux and equals to permeability
divided by the skin layer thickness of the membrane. Commercially
available gas separation polymer membranes, such as CA, polyimide,
and polysulfone membranes formed by phase inversion and solvent
exchange methods have an asymmetric integrally skinned membrane
structure. Such membranes are characterized by a thin, dense,
selectively semipermeable surface "skin" and a less dense
void-containing (or porous), non-selective support region, with
pore sizes ranging from large in the support region to very small
proximate to the "skin." Another type of commercially available gas
separation polymer membrane is the thin film composite (or TFC)
membrane, comprising a thin selective skin deposited on a porous
support. TFC membranes can be formed from CA, polysulfone,
polyethersulfone, polyamide, polyimide, polyetherimide, cellulose
nitrate, polyurethane, polycarbonate, polystyrene, etc.
[0023] The compressed stream 185 is separated into permeate stream
195 and retentate stream 200 in membrane separation zone 190.
Retentate stream 200, which will contain comprises helium, carbon
monoxide, carbon dioxide, small amounts of water, and very low
levels (in the ppm range) of hydrogen and hydrocarbons is removed
from the system.
[0024] There is a significant pressure drop across the membrane. As
a result, permeate stream 195 is compressed in compression zone 205
to a pressure of about 3 MPa to about 4 MPa. The compressed stream
210 is fed into the oxidation zone 115 along with feed 105 and
oxygen stream 110. The compressed stream 210 can be fed into the
oxidation zone separately, as shown, or it can be mixed with the
feed 105 before entering the oxidation zone.
[0025] The compression zones 180 and 205 can be a single
compressors, or there can be two or more compressors in either
zone.
[0026] Alternatively, the tail gas stream 165 can be compressed in
compression zone 180 before being divided into streams 170 and 175.
If compression zone 180 includes more than one compressor, the tail
gas stream 165 can be divided into streams 170 and 175 between the
compressors in the compression zone 180.
[0027] In another alternative, the retentate stream 200 can be
removed from the system after the compression zone 205. If
compression zone 205 includes more than one compressor, the
retentate stream 200 can be removed between the compressors in the
compression zone 205.
[0028] In another alternative, a portion of the helium rich
permeate stream 195 can be removed from the system before or after
compression zone 205, or if compression zone 205 includes more than
one compressor, the permeate stream 195 can be removed between the
compressors in the compression zone 205. This can be done to avoid
build-up of various components in the system.
Example
[0029] A simulation was run making the following assumptions. The
feed gas contains only hydrogen (10%), nitrogen (30%) and helium
(60%). The oxygen stream is high purity oxygen (100.0%). The
residual oxygen after oxidation is 1.0%. The assumed helium
recovery of PSA is 75%. The targeted helium recovery is 98%. Table
1 is a material balance of a system reaching a helium recovery of
98% on a molar basis.
The streams are as follows: [0030] 105: Feed Stream (gas stream)
[0031] 110: Oxygen Stream [0032] 120: Stream downstream of
Oxidation (first vapor stream) [0033] 145: PSA Feed Stream (second
vapor stream) [0034] 150: Liquid Condensate (second liquid stream)
[0035] 160: Pure Helium Stream, ready for export (purified helium)
[0036] 165: PSA Tail Gas to be compressed before membranes (tail
gas stream) [0037] 175: Purge Stream from PSA Tail Gas: none [0038]
185: Membrane Feed gas stream (compressed stream) [0039] 200:
Membrane Residue gas stream (leaves unit) (retentate stream) [0040]
210: Compressed Membrane Permeate Gas stream to be recycled to
catalytic oxidation (compressed stream).
TABLE-US-00001 [0040] TABLE 1 Stream 105 110 120 145 150 160 165
175 185 200 210 Pressure, MPa (abs) 3.00 3.00 2.95 2.90 2.90 2.80
0.13 3.00 2.80 3.00 Temperature, .degree. C. 40 40 830 40 40 38 38
40 35 40 Flow, Nm.sup.3/h 10,000 585 12,192 11,220 972 5,879 5,341
0.0 5,323 3,207 2,106 Composition, mole % Methane 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 Nitrogen 30.0 0.0 26.4 28.7 0.0 0.0 60.4
60.6 93.6 10.7 Water 0.0 0.0 8.3 0.3 100.0 0.0 0.6 0.3 0.0 0.3
Helium 60.0 0.0 64.3 69.9 0.0 100.0 36.7 36.8 3.8 87.3 Oxygen 0.0
100.0 1.0 1.1 0.0 0.0 2.3 2.3 2.7 1.7 Hydrogen 10.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0
[0041] By "about" we mean within 10% of the value, or within 5%, or
within 1%.
[0042] While at least one exemplary embodiment has been presented
in the foregoing detailed description of the invention, it should
be appreciated that a vast number of variations exist. It should
also be appreciated that the exemplary embodiment or exemplary
embodiments are only examples, and are not intended to limit the
scope, applicability, or configuration of the invention in any way.
Rather, the foregoing detailed description will provide those
skilled in the art with a convenient road map for implementing an
exemplary embodiment of the invention. It being understood that
various changes may be made in the function and arrangement of
elements described in an exemplary embodiment without departing
from the scope of the invention as set forth in the appended
claims.
Specific Embodiments
[0043] While the following is described in conjunction with
specific embodiments, it will be understood that this description
is intended to illustrate and not limit the scope of the preceding
description and the appended claims.
[0044] A first embodiment of the invention is a process of
increasing recovery of helium from a stream containing helium
comprising introducing the stream containing helium and at least
one oxidizable component into an oxidation zone in the presence of
oxygen to oxidize the at least one oxidizable component forming a
first vapor stream and a first liquid stream; introducing at least
a portion of the first vapor stream into a pressure swing
adsorption zone to form a purified helium stream and a tail gas
stream, the tail gas stream containing helium; compressing at least
a portion of the tail gas stream; introducing at least a portion of
the compressed tail gas stream into a membrane separation zone to
form a helium rich permeate stream and a retentate stream;
compressing at least a portion of the helium rich permeate stream;
and introducing the compressed helium rich permeate stream into the
oxidation zone. An embodiment of the invention is one, any or all
of prior embodiments in this paragraph up through the first
embodiment in this paragraph further comprising condensing the
first vapor stream before introducing the at least the portion of
the first vapor stream into the pressure swing adsorption zone. An
embodiment of the invention is one, any or all of prior embodiments
in this paragraph up through the first embodiment in this paragraph
further comprising separating the condensed first vapor stream into
a second vapor stream and a second liquid stream; and wherein
introducing the at least the portion of the first vapor stream into
the pressure swing adsorption zone comprises introducing the second
vapor stream into the pressure swing adsorption zone. An embodiment
of the invention is one, any or all of prior embodiments in this
paragraph up through the first embodiment in this paragraph wherein
the oxidation zone comprises a catalytic oxidation zone. An
embodiment of the invention is one, any or all of prior embodiments
in this paragraph up through the first embodiment in this paragraph
further comprising removing a portion of the tail gas stream. An
embodiment of the invention is one, any or all of prior embodiments
in this paragraph up through the first embodiment in this paragraph
wherein the portion of the tail gas stream is removed before
compressing the at least the portion of the tail gas stream. An
embodiment of the invention is one, any or all of prior embodiments
in this paragraph up through the first embodiment in this paragraph
wherein the portion of the tail gas stream is removed after
compressing the at least the portion of the tail gas stream. An
embodiment of the invention is one, any or all of prior embodiments
in this paragraph up through the first embodiment in this paragraph
wherein the portion of the tail gas stream is removed after
compressing the at least the portion of the helium rich permeate
stream. An embodiment of the invention is one, any or all of prior
embodiments in this paragraph up through the first embodiment in
this paragraph further comprising removing a portion of the helium
rich permeate gas stream. An embodiment of the invention is one,
any or all of prior embodiments in this paragraph up through the
first embodiment in this paragraph wherein the portion of the
helium rich permeate gas stream is removed before compressing the
at least the portion of the helium rich permeate gas stream. An
embodiment of the invention is one, any or all of prior embodiments
in this paragraph up through the first embodiment in this paragraph
wherein the portion of the helium rich permeate stream is removed
after compressing the at least the portion of the helium rich
permeate stream. An embodiment of the invention is one, any or all
of prior embodiments in this paragraph up through the first
embodiment in this paragraph wherein the tail gas stream has a
helium content of about 30-35%. An embodiment of the invention is
one, any or all of prior embodiments in this paragraph up through
the first embodiment in this paragraph wherein the helium rich
permeate stream has a helium content of at least about 70%. An
embodiment of the invention is one, any or all of prior embodiments
in this paragraph up through the first embodiment in this paragraph
wherein the stream containing helium has a helium content of about
50-90%, the tail gas stream has a helium content of about 30-60%,
the helium rich permeate stream has a helium content of at least
about 70%, and the purified helium stream has a helium content of
at least about 99%.
[0045] A second embodiment of the invention is a process of
increasing recovery of helium from a stream containing helium
comprising introducing the stream containing helium into a
catalytic oxidation zone in the presence of oxygen to oxidize the
at least one oxidizable component forming a first vapor stream and
a first liquid stream, wherein the stream containing helium has a
helium content of about 55-60%; condensing the first vapor stream
from the catalytic oxidation zone; separating the condensed first
vapor stream into a second liquid stream and a second vapor stream;
introducing the second vapor stream into a pressure swing
adsorption zone to form a purified helium stream having a helium
content of at least about 99% and a tail gas stream having a helium
content of about 30-35%; compressing at least a portion of the tail
gas stream; introducing at least a portion of the compressed tail
gas stream into a membrane separation zone to form a helium rich
permeate stream having a helium content of at least about 70% and a
retentate stream; compressing the helium rich permeate stream; and
introducing the compressed helium rich permeate stream into the
catalytic oxidation zone. An embodiment of the invention is one,
any or all of prior embodiments in this paragraph up through the
second embodiment in this paragraph further comprising removing a
portion of the tail gas stream. An embodiment of the invention is
one, any or all of prior embodiments in this paragraph up through
the second embodiment in this paragraph wherein the portion of the
tail gas stream is removed before compressing the at least the
portion of the tail gas stream. An embodiment of the invention is
one, any or all of prior embodiments in this paragraph up through
the second embodiment in this paragraph further comprising removing
a portion of the helium rich permeate gas stream. An embodiment of
the invention is one, any or all of prior embodiments in this
paragraph up through the second embodiment in this paragraph
wherein the portion of the helium rich permeate gas stream is
removed before compressing the at least the portion of the helium
rich permeate gas stream.
[0046] A third embodiment of the invention is an apparatus for
recovery of helium from a stream containing helium comprising an
oxidation zone having a feed inlet, an oxygen inlet, a liquid
outlet, and a gas outlet; a condenser having an inlet and an
outlet, the inlet of the condenser being in fluid communication
with the gas outlet of the oxidation zone; a separator having an
inlet, a liquid outlet, and a gas outlet, the inlet of the
separator in fluid communication with the outlet of the condenser;
a pressure swing adsorption zone having an inlet, a purified helium
outlet, and a tail gas outlet, the inlet of the pressure swing
adsorption zone being in fluid communication with the outlet of the
separator; a first compression zone having an inlet and an outlet,
the inlet of the first compression zone being in fluid
communication with the tail gas outlet of the pressure swing
adsorption system; a membrane separation zone having an inlet, a
permeate outlet, and a retentate outlet, the inlet of the membrane
separation zone being in fluid communication with the tail gas
outlet of the pressure swing adsorption zone; and a second
compression zone having an inlet and an outlet, the inlet of the
second compression zone being in fluid communication with the
permeate outlet of the membrane separation zone, and the outlet of
the second compression zone being in fluid communication with the
oxidation zone.
[0047] Without further elaboration, it is believed that using the
preceding description that one skilled in the art can utilize the
present invention to its fullest extent and easily ascertain the
essential characteristics of this invention, without departing from
the spirit and scope thereof, to make various changes and
modifications of the invention and to adapt it to various usages
and conditions. The preceding preferred specific embodiments are,
therefore, to be construed as merely illustrative, and not limiting
the remainder of the disclosure in any way whatsoever, and that it
is intended to cover various modifications and equivalent
arrangements included within the scope of the appended claims.
[0048] In the foregoing, all temperatures are set forth in degrees
Celsius and, all parts and percentages are by weight, unless
otherwise indicated.
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